docs: def to_datetime(t):
      """Convert 6-part time tuple into datetime object.
      """
      if t is None:
          return None
  
      # extract values
      year, mon, day, h, m, s = t
  
      # assume the values are valid
      try:
          return datetime(year, mon, day, h, m, s)
      except ValueError:
          pass
  
      # sanitize invalid values
      mday = (0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31)
      if mon < 1:
          mon = 1
      if mon > 12:
          mon = 12
      if day < 1:
          day = 1
      if day > mday[mon]:
          day = mday[mon]
      if h > 23:
          h = 23
      if m > 59:
          m = 59
      if s > 59:
          s = 59
      if mon == 2 and day == 29:
          try:
              return datetime(year, mon, day, h, m, s)
          except ValueError:
              day = 28
      return datetime(year, mon, day, h, m, s)